Abstract : This abstract discloses an apparatus for rotating subhuman primate animal test subjects about one ore more axes to minimize trauma during simulated zero or micro-gravity studies. The timed roto-positioning apparatus has a frame, a subframe rotatably attached to the frame and a carried for a primate restraint system rotatably attached to the subframe. Two motors, controlled by a programmable controller, individually rotate the subframe and the carrier according to a preselected sequence. The preferred embodiment is a modified A-frame structure made from welded channel aluminum beans and equipped with casters and lifters to move and securely position the apparatus. A tube with rotatable fittings is used to supply drinking water to test animals and electrical slip rings are used for transmitting physiological sensor signals from the test animal through the rotating connections of the carrier, subframe and frame. Radio telemetry may be used in place of the electrical slip rings. The invention also includes the method of rotating an immobilized or immobile test subject or patient along at least one axis to minimize trauma and to simulate weightlessness.